Looking for resistive sheet material

[Ken_A]

Hello,

I'm looking for electrically resistive sheet material from which to make custom potentiometers. These will be slider type pots, not rotary, with track width varying along the length to give particular resistance versus position characteristic.

Can anyone suggest a source of suitable material, something along the lines of carbon loaded plastic sheet?

I'm aware of the Adafruit pressure sensitive conductive sheet (Velostat/Linqstat), but this is rather high resistance at about 30 kohm/sq, and I think might have limited life with a slider contact dragging across it. I also know about Teledeltos conductive paper, but that has same drawbacks.

Ideally I'm looking for hard sheet material with 100 to 1000 ohm/sq sheet resistivity. And it would need to be available for a hobbyist in the UK in sensibly small quantity.

Many thanks for any help or suggestions.

 

[Gryd3]

Hello,

I'm looking for electrically resistive sheet material from which to make custom potentiometers. These will be slider type pots, not rotary, with track width varying along the length to give particular resistance versus position characteristic.

Can anyone suggest a source of suitable material, something along the lines of carbon loaded plastic sheet?

I'm aware of the Adafruit pressure sensitive conductive sheet (Velostat/Linqstat), but this is rather high resistance at about 30 kohm/sq, and I think might have limited life with a slider contact dragging across it. I also know about Teledeltos conductive paper, but that has same drawbacks.

Ideally I'm looking for hard sheet material with 100 to 1000 ohm/sq sheet resistivity. And it would need to be available for a hobbyist in the UK in sensibly small quantity.

Many thanks for any help or suggestions.

You stated a 'limited' life of one of the above products. How long do you need it to last?
Can you not order existing slides to do this for you?

 

[Ken_A]

Hi Gryd3,
Well, I guess I'd want it to last for many slider operations, at least hundreds.
AS for ordering existing slides, I assume you mean off-the-shelf slide pots. These all seem to be small, and I was hoping to
achieve better precision and finer control by making my own large slides.

 

[Gryd3]

Ken, finer control may not be possible unless you sink some serious time to make sure they devices are built to very tight specifications... you need to make sure that the film you find or order is accurate enough as well... as any variation on the conductor surface will cause variation for your application.

How large do you need? There may be no other option than to try to build yourself...
5 and 6 inch lengths are available at Digikey ... I'm sure you can get larger ...
Depending on the accuracy you need, or the application you are using it on... there are other ways you could make longer slides...

 

[Ken_A]

Hi Gryd3,
Well, I guess I'd want it to last for many slider operations, at least hundreds.
AS for ordering existing slides, I assume you mean off-the-shelf slide pots. These all seem to be small, and I was hoping to
achieve better precision and finer control by making my own large slides.

 

[Ken_A]

Hi Again,
Yes, you are right, on looking at the RS website I now find that slide pots by Alps are available with
length of about 130mm, and with log characteristic, which will be close enough, and they are not too expensive.
So I will purchase a couple of these to try out, and so might not need to make my own.
Many thanks for your advice.
Ken.

 

[Gryd3]

Hi Again,
Yes, you are right, on looking at the RS website I now find that slide pots by Alps are available with
length of about 130mm, and with log characteristic, which will be close enough, and they are not too expensive.
So I will purchase a couple of these to try out, and so might not need to make my own.
Many thanks for your advice.
Ken.

Your welcome Ken.
Alternatively, if you get your hands on a rotary pot, you can make some magic happen with a belt. The Slide will move the belt and cause the rotary dial to move. It's bulky, but would allow you to make almost any size slide you could want.
I'm unsure the quantity that you need, but I'm thinking this will be an easier solution than fidgeting with raw materials.

Best of luck on your project. We hope to see you around here more.

 

[Ken_A]

Many thanks.
I think I should close this thread now, but am not sure how to do so.
Can you advise, or close it for me?
Thanks again, Ken.

 

[Gryd3]

You can contact a moderator like @KrisBlueNZ or @(*steve*) if you need a thread locked or moved.
The threads in Electronics Point typically don't get locked when they are done unless it is to prevent excessive fluff or filler posts.